#include #include#include
#define BUCKETCOUNT 16
structhashEntry
{const char*key;char*value;struct hashEntry*next;
};
typedefstructhashEntry entry;structhashTable
{
entry bucket[BUCKETCOUNT];//先默认定义16个桶
};
typedefstructhashTable table;//初始化哈希表
void initHashTable(table*t)
{inti;if (t == NULL)return;for (i = 0; i < BUCKETCOUNT; ++i) {
t->bucket[i].key =NULL;
t->bucket[i].value =NULL;
t->bucket[i].next =NULL;
}
}//释放哈希表
void freeHashTable(table*t)
{inti;
entry* e,*ep;if (t == NULL)return;for (i = 0; i
e= &(t->bucket[i]);while (e->next !=NULL) {
ep= e->next;
e->next = ep->next;
free(ep->key);
free(ep->value);
free(ep);
}
}
}//哈希散列方法函数
int keyToIndex(const char*key)
{intindex , len , i;if (key == NULL)return -1;
len=strlen(key);
index= (int)key[0];for (i = 1; i
index*= 1103515245 + (int)key[i];
}
index>>= 27;
index&= (BUCKETCOUNT - 1);returnindex;
}//在堆上分配足以保存str的内存//并拷贝str内容到新分配位置
char* strDup(const char*str)
{intlen;char*ret;if (str == NULL)returnNULL;
len=strlen(str);
ret= (char*)malloc(len + 1);if (ret !=NULL) {
memcpy(ret , str , len);
ret[len]= ‘\0‘;
}returnret;
}//向哈希表中插入数据//insertEntry(&t , "电脑型号" , "华硕 X550JK 笔记本电脑");
int insertEntry(table* t , const char* key , const char*value)
{intindex , vlen1 , vlen2;
entry* e , *ep;if (t == NULL || key == NULL || value ==NULL) {return -1;
}
index=keyToIndex(key);
printf("index = %d\n",index);if (t->bucket[index].key ==NULL) {
t->bucket[index].key =strDup(key);
t->bucket[index].value =strDup(value);
}else{
e= ep = &(t->bucket[index]);while (e != NULL) { //先从已有的找
if (strcmp(e->key , key) == 0) {//找到key所在，替换值
vlen1 =strlen(value);
vlen2= strlen(e->value);if (vlen1 >vlen2) {
free(e->value);
e->value = (char*)malloc(vlen1 + 1);
}
memcpy(e->value , value , vlen1 + 1);return index; //插入完成了
}
ep=e;
e= e->next;
}//end while(e...//没有在当前桶中找到//创建条目加入
e = (entry*)malloc(sizeof(entry));
e->key =strDup(key);
e->value =strDup(value);
e->next =NULL;
ep->next =e;
}returnindex;
}//在哈希表中查找key对应的value//找到了返回value的地址，没找到返回NULL
const char* findValueByKey(const table* t , const char*key)
{intindex;const entry*e;if (t == NULL || key ==NULL) {returnNULL;
}
index=keyToIndex(key);
e= &(t->bucket[index]);if (e->key == NULL) return NULL;//这个桶还没有元素
while (e !=NULL) {if (0 == strcmp(key , e->key)) {return e->value; //找到了，返回值
}
e= e->next;
}returnNULL;
}//在哈希表中查找key对应的entry//找到了返回entry，并将其从哈希表中移除//没找到返回NULL
entry* removeEntry(table* t , char*key)
{intindex;
entry* e,*ep; //查找的时候，把ep作为返回值
if (t == NULL || key ==NULL) {returnNULL;
}
index=keyToIndex(key);
e= &(t->bucket[index]);while (e !=NULL) {if (0 == strcmp(key , e->key)) {//如果是桶的第一个
if (e == &(t->bucket[index])) {//如果这个桶有两个或以上元素//交换第一个和第二个，然后移除第二个
ep = e->next;if (ep !=NULL) {
entry tmp= *e; //做浅拷贝交换
*e = *ep;//相当于链表的头节点已经移除
*ep = tmp; //这就是移除下来的链表头节点
ep->next =NULL;
}else {//这个桶只有第一个元素
ep = (entry*)malloc(sizeof(entry));*ep = *e;
e->key = e->value =NULL;
e->next =NULL;
}
}else{//如果不是桶的第一个元素//找到它的前一个(这是前面设计不佳导致的多余操作)
ep = &(t->bucket[index]);while (ep->next != e)ep = ep->next;//将e从中拿出来
ep->next = e->next;
e->next =NULL;
ep=e;
}returnep;
}//end if(strcmp...
e = e->next;
}returnNULL;
}void printTable(table*t)
{inti;
entry*e;if (t == NULL)return;for (i = 0; i
printf("\nbucket[%d]:\n", i);
e= &(t->bucket[i]);while (e->key !=NULL) {
printf("\t%s\t=\t%s\n" , e->key , e->value);if (e->next == NULL)break;
e= e->next;
}
}
}intmain()
{
table t;
initHashTable(&t);
insertEntry(&t , "电脑型号" , "华硕 X550JK 笔记本电脑");
insertEntry(&t , "操作系统" , "Windows 8.1 64位 (DirectX 11)");
insertEntry(&t , "处理器" , "英特尔 Core i7 - 4710HQ @ 2.50GHz 四核");
insertEntry(&t , "主板" , "华硕 X550JK(英特尔 Haswell)");
insertEntry(&t , "内存" , "4 GB(Hynix / Hyundai)");
insertEntry(&t , "主硬盘" , "日立 HGST HTS541010A9E680(1 TB / 5400 转 / 分)");
insertEntry(&t , "显卡" , "NVIDIA GeForce GTX 850M (2 GB / 华硕)");
insertEntry(&t , "显示器" , "奇美 CMN15C4(15.3 英寸)");
insertEntry(&t , "光驱" , "松下 DVD - RAM UJ8E2 S DVD刻录机");
insertEntry(&t , "声卡" , "Conexant SmartAudio HD @ 英特尔 Lynx Point 高保真音频");
insertEntry(&t , "网卡" , "瑞昱 RTL8168 / 8111 / 8112 Gigabit Ethernet Controller / 华硕");
insertEntry(&t , "主板型号" , "华硕 X550JK");
insertEntry(&t , "芯片组" , "英特尔 Haswell");
insertEntry(&t , "BIOS" , "X550JK.301");
insertEntry(&t , "制造日期" , "06 / 26 / 2014");
insertEntry(&t , "主人" , "就是我");
insertEntry(&t , "价格" , "六十张红色毛主席");
insertEntry(&t , "主硬盘" , "换了个120G的固态");
entry* e = removeEntry(&t , "主板型号");if (e !=NULL) {
puts("找到后要释放");
free(e->key);
free(e->value);
free(e);
e=NULL;
}
printTable(&t);const char* keys[] = { "显示器" , "主人","没有" , "处理器"};for (int i = 0; i < 4; ++i) {const char* value = findValueByKey(&t , keys[i]);if (value !=NULL) {
printf("find %s\t=\t%s\n",keys[i], value);
}else{
printf("not found %s\n",keys[i]);
}
}
freeHashTable(&t);
getchar();return 0;
}
